Life Adapts to a Sealed, Poison Cave

In southeastern Romania in Constanta county near the Black Sea scientists discovered a cave that had been cut off from the outside world throughout history. Yet, even in a sealed, poison cave, life adapts.

Scientists estimate that the cave was sealed off 5.5 million years ago, and its air is low in oxygen (10%) and high in carbon dioxide (3%). That is almost one-third the amount of oxygen and 100 times more carbon dioxide as the air we breathe. The air and water in the cave also contain high levels of hydrogen sulfide and ammonia. The cave is named Movile Cave, and it is full of life. Biologists have identified 48 species, and 33 of them are found nowhere else.

The food chain in the cave is based on chemosynthesis using sulfur instead of photosynthesis which requires sunlight. Bacteria which oxidize sulfur and methane release nutrients used by other bacteria and fungi. They, in turn, create microbial mats on the cave wall. Those mats are grazed by herbivorous creatures which are consumed by carnivorous creatures such as spiders, leeches, and water scorpions. Contrary to what the media has reported, life didn’t start in the cave. Instead, life has adapted to the cave environment.